1. Field of the Invention
The present invention relates to a sealing agent to be filled into a grommet, a method of sealing a wire harness with the sealing agent, and a sealing construction of the wire harness. More particularly, in order to waterproof the wire harness reliably, the present invention is intended to allow the sealing agent to have a high degree of penetration performance to fill gaps between groups of electric wires of the wire harness inserted into the grommet. Further, the present invention is intended to harden the sealing agent in a short period of time to accomplish a waterproof operation with high efficiency.
2. Description of Related Art
According to the conventional art, a wire harness W/H is positioned by penetrating it through a through-hole formed on a car body panel (P), as shown in FIG. 5: An operator inserts the wire harness W/H into a grommet 1 made of rubber to bring it into close contact with a small-diameter section 1a of the grommet 1. An engaging groove 1c formed on the peripheral surface of a large-diameter section 1b of the grommet 1 fits into the peripheral wall of a through-hole 2 of the car body panel (P), and a lip 1d formed on a part of the grommet 1 to be installed on the car body is brought into close contact with the car body panel (P). In this manner, the operator seals the wire harness W/H.
In inserting the grommet-installed wire harness W/H into an engine room and placing it at position, it is necessary to waterproof the wire harness W/H. To this end, referring to FIG. 6, inside the grommet, electric wires (w) constituting the wire harness W/H are not tied into a bundle with a tape but separated from each other. In this state, a sealing agent 3 is injected from the large-diameter section 1b of the grommet 1 into the gaps between the adjacent electric wires (w) and the gaps between the electric wires (w) and the inner peripheral surface of the grommet 1.
The above-described conventional art has, however, a problem that the sealing agent 3 is incapable of penetrating readily into all the gaps, because the gaps between the adjacent electric wires (w) are small and in addition, the viscosity of the conventional sealing agent 3 is as high as 1,000 cps-2,000 cps.
A sealing agent having a low viscosity may be used to improve its flowability and hence its penetration property. But the problem is that it takes more than 15 minutes to harden. Thus, in that period of time, the sealing agent 3 flows downward from the grommet-installing region of the wire harness and is thus incapable of completely filling the gaps between the adjacent electric wires (w) inside the grommet.